The public health response to an outbreak of border-spill malaria along China-Myanmar border

Abstract

Introduction Malaria importation can be caused by cross-border movement either of both people and anopheline mosquitoes. However, there still lacks robust evidence of imported malaria caused by Plasmodium spp. infected anopheles along international border areas (border-spill malaria). The objectives of this study were to confirm whether an outbreak of Plasmodium vivax malaria is border-spill malaria and assess the effects of China’s public health response along China-Myanmar border. Methods Epidemiological, parasitological and entomological investigations were conducted to investigate the outbreak of border-spill malaria. Meanwhile, comprehensive interventions were carried out to prevent further transmission and reintroduction of malaria. Results Rapid diagnostic testing, microscopy and polymerase chain reaction were performed and the infections were confirmed as P. vivax. A total of 22 (9.21%) of 239 workers contracted P. vivax during the outbreak. Multivariate logistic regression analysis identified that the distance of worker shelters in China within 300 meters to the internally displaced person (IDP) camps in Myanmar was a risk factors associated with malaria infection (adjusted odds ratio 7.5920; 95% confidence interval, 2.6079–22.1013; P = 0.0002). After comprehensive interventions, malaria transmission was successfully interpreted and prevented at the project site till the completion of project on 14 January 2020, and recurrence of P. vivax malaria was not detected by the end of 2020. Conclusion This study provided robust evidence of border-spill malaria along China-Myanmar border. Malaria parasite reservoir and distance travelled by female anopheline mosquitoes are two determinants for border-spill malaria. The public health response to the outbreak indicates that the malaria surveillance and response system works well in preventing reintroduction of malaria. However, prevention of border-spill malaria is still a major challenge in the Yunnan border area, China.

Artemisinin-naphthoquine plus lower-dose primaquine to treat and prevent recurrence of Plasmodium vivax malaria: an open-label randomized and non-inferiority trial

“…However, the homologous recurrence can more directly re ects recrudescence and relapse, so it is more indicative in showing radical cure e cacy [14,37]. The Myanmar Kachin Special Region II is still malaria endemicity [8, 9,27,28,38,39]. In this study without genotyping homologous and heterologous infections, the e cacy of the prevention of P. vivax recurrence (renewed parasitaemia) should be more indicative.…”

Artemisinin-naphthoquine plus lower-dose primaquine to treat and prevent recurrence of Plasmodium vivax malaria: an open-label randomized and non-inferiority trial

“…However, all patients in the two groups had the same exposure to re-infection, so results without genotyping homologous or heterologous infections would be comparable. KR2 is still malaria endemic in Myanmar II [ 8 , 9 , 27 , 28 , 36 , 37 ]. In this study without genotyping homologous and heterologous infections, the efficacy in prevention of P. vivax recurrence (renewed parasitaemia) should be more indicative.…”

Cooperative Sentinel Surveillance of Malaria in Laiza and Nearby Areas of Myanmar and Importation Threat Monitoring — China, 2019–2023

“…Anopheles minimus was the predominant malaria vector in LNA, with an 85.87% prevalence among Anopheles spp in 2018. It was reported to have a 1.69% sporozoite infection rate of P. vivax (9). Any slight decrease or inadequacy in interventions could trigger a resurgence of malaria.…”

“…Malaria transmission is continuous throughout the year, with all human malaria parasite species present in the area (7). Control measures have resulted in Plasmodium vivax (P. vivax) becoming the predominant malaria parasite over time (7)(8)(9).…”